/**
 * Software License, Version 1.0
 * 
 * Copyright 2003 The Trustees of Indiana University.  All rights reserved.
 * 
 *
 *Redistribution and use in source and binary forms, with or without 
 *modification, are permitted provided that the following conditions are met:
 *
 *1) All redistributions of source code must retain the above copyright notice,
 * the list of authors in the original source code, this list of conditions and
 * the disclaimer listed in this license;
 *2) All redistributions in binary form must reproduce the above copyright 
 * notice, this list of conditions and the disclaimer listed in this license in
 * the documentation and/or other materials provided with the distribution;
 *3) Any documentation included with all redistributions must include the 
 * following acknowledgement:
 *
 *"This product includes software developed by the Community Grids Lab. For 
 * further information contact the Community Grids Lab at 
 * http://communitygrids.iu.edu/."
 *
 * Alternatively, this acknowledgement may appear in the software itself, and 
 * wherever such third-party acknowledgments normally appear.
 * 
 *4) The name Indiana University or Community Grids Lab or NaradaBrokering, 
 * shall not be used to endorse or promote products derived from this software 
 * without prior written permission from Indiana University.  For written 
 * permission, please contact the Advanced Research and Technology Institute 
 * ("ARTI") at 351 West 10th Street, Indianapolis, Indiana 46202.
 *5) Products derived from this software may not be called NaradaBrokering, 
 * nor may Indiana University or Community Grids Lab or NaradaBrokering appear
 * in their name, without prior written permission of ARTI.
 * 
 *
 * Indiana University provides no reassurances that the source code provided 
 * does not infringe the patent or any other intellectual property rights of 
 * any other entity.  Indiana University disclaims any liability to any 
 * recipient for claims brought by any other entity based on infringement of 
 * intellectual property rights or otherwise.  
 *
 *LICENSEE UNDERSTANDS THAT SOFTWARE IS PROVIDED "AS IS" FOR WHICH NO 
 *WARRANTIES AS TO CAPABILITIES OR ACCURACY ARE MADE. INDIANA UNIVERSITY GIVES
 *NO WARRANTIES AND MAKES NO REPRESENTATION THAT SOFTWARE IS FREE OF 
 *INFRINGEMENT OF THIRD PARTY PATENT, COPYRIGHT, OR OTHER PROPRIETARY RIGHTS. 
 *INDIANA UNIVERSITY MAKES NO WARRANTIES THAT SOFTWARE IS FREE FROM "BUGS", 
 *"VIRUSES", "TROJAN HORSES", "TRAP DOORS", "WORMS", OR OTHER HARMFUL CODE.  
 *LICENSEE ASSUMES THE ENTIRE RISK AS TO THE PERFORMANCE OF SOFTWARE AND/OR 
 *ASSOCIATED MATERIALS, AND TO THE PERFORMANCE AND VALIDITY OF INFORMATION 
 *GENERATED USING SOFTWARE.
 */
package cgl.narada.wsinfra.wse.matching;

import java.util.Calendar;
import java.util.Enumeration;

import org.apache.xmlbeans.XmlCursor;

import cgl.narada.wsinfra.exception.WsFaultException;
import cgl.narada.wsinfra.schemas.eventing.DeliveryType;
import cgl.narada.wsinfra.schemas.eventing.FilterType;
import cgl.narada.wsinfra.schemas.eventing.SubscribeDocument;
import cgl.narada.wsinfra.wse.WseFaults;

/** This is a utility class which validates subscriptions that have
    specified in requests.

    @author Shrideep Pallickara
    $Date: 2005/07/29 22:41:30 $
    $Revision: 1.4 $
*/

public class SubscriptionValidator {
  private static final
  SubscriptionValidator instance = new SubscriptionValidator();

  private MatchingCapabilityFactory matchingCapabilityFactory;
  private WseFaults wseFaults;
  private static final String defaultDeliveryMode=
  "http://schemas.xmlsoap.org/ws/2004/08/eventing/DeliveryModes/Push";

  private static final String defaultFilterDialect =
  "http://www.w3.org/TR/1999/REC-xpath-19991116";

  private boolean debug=true;
  private String moduleName = "SubscriptionValidator: ";

  private SubscriptionValidator() {
    matchingCapabilityFactory = MatchingCapabilityFactory.getInstance();
    wseFaults = WseFaults.getInstance();
  }


  public static SubscriptionValidator getInstance() {
    return instance;
  }


  public void validateSubscription(SubscribeDocument subscribeDocument)
    throws WsFaultException {
    SubscribeDocument.Subscribe subscribe =
      subscribeDocument.getSubscribe();



    if (subscribe.isSetFilter()) {
      FilterType filter = subscribe.getFilter();
      checkSpecifiedFilter(filter);
    }

    if (subscribe.isSetExpires()) {
      Object expiry = subscribe.getExpires();
      checkSpecifiedExpiry(expiry);
    } else {
      /** The sinks is requesting a subscription whic does not expire. We will
	  not allows that presently. */
      throw new WsFaultException(wseFaults.getInvalidExpirationTime(),
				 wseFaults.getInvalidExpirationTimeReason());
    }

    DeliveryType delivery = subscribe.getDelivery();
    checkSpecifiedDeliveryMode(delivery);
  }


  private void checkSpecifiedFilter(FilterType filter)
    throws WsFaultException {
    XmlCursor filterCursor = filter.newCursor();
    String dialect = filter.getDialect();
    String constraint = filterCursor.getTextValue();
    filterCursor.dispose();

    if (debug) {
      System.out.println(moduleName + "Specified Filter Dialect->" + dialect +
			 ", Filter constraint->" + constraint );
    }

    if (dialect == null) {
      /** This corresponds to the implied dialect. No further processing
	  required */
      return;
    }

    Enumeration supportedDialects =
      matchingCapabilityFactory.getSupportedDialects();
    boolean dialectSupported = false;

    while (supportedDialects.hasMoreElements()) {
      String _dialect = (String) supportedDialects.nextElement();
      if (_dialect.equals(dialect)) {
	dialectSupported = true;
	break;
      }
    }

    if (!dialectSupported) {
      throw new WsFaultException(wseFaults.getFilteringRequestedUnavailable(),
			  wseFaults.getFilteringRequestedUnavailableReason() );
    }
  }


  private void checkSpecifiedExpiry(Object expiry)
    throws WsFaultException {
    if (debug) {
      System.out.println(moduleName + "Expiry is " + expiry );
    }

    if (expiry instanceof Calendar) {
      System.out.println(moduleName + "The expiry is an instance of Calendar");
      Calendar currentTime = Calendar.getInstance();
      Calendar expiresAt = (Calendar) expiry;
      boolean isInPast = expiresAt.before(currentTime);

      if (isInPast) {
	System.out.println(moduleName +
			   "The specified expiry time is in the past");
	throw new WsFaultException(wseFaults.getInvalidExpirationTime(),
				wseFaults.getInvalidExpirationTimeReason());
      }
      return;
    }

    /** If the time specified is not absolute time we throw an error.
	NTBI: Deal with non-negative durations that might be specified */
    throw new WsFaultException(wseFaults.getInvalidExpirationTime(),
				wseFaults.getInvalidExpirationTimeReason());
  }


  private void checkSpecifiedDeliveryMode(DeliveryType delivery)
					  throws WsFaultException {
    if (debug) {
      System.out.println(moduleName +
			 "Delivery Mode-> set=" + delivery.isSetMode() +
			 " mode=" + delivery.getMode() );
    }

    if (!delivery.isSetMode()) {
      /** The default mode will be used */
      return;
    }

    String deliveryMode = delivery.getMode();

    if (deliveryMode.equals(defaultDeliveryMode)) {
      return;
    }

    throw new WsFaultException(wseFaults.getDeliveryModeUnavailable(),
			       wseFaults.getDeliveryModeUnavailableReason());
  }

}
